Conventionally, as a method of coating a coating liquid on a substrate such as, for example, a semiconductor wafer or a glass substrate, a so-called spin coating method has been widely known. The spin coating method supplies a coating liquid from a coating nozzle to the center of a substrate while rotating the substrate so that the coating liquid is spread over the substrate by a centrifugal force and thus coated on the surface of the substrate.
In the case of using the spin coating method, the coating liquid supplied to the substrate is spread by a high speed rotation, and thus, most of the supplied coating liquid is scattered and wasted from the outer peripheral portion of the substrate.
Therefore, in order to reduce the waste of such a coating liquid, for example, Japanese Patent Laid-open Publication No. 2011-167603 has suggested a method of coating a coating liquid on a substrate by drawing out the coating liquid by a capillary phenomenon from an ejection port of a coating nozzle (hereinafter, sometimes referred to as a “capillary coating method”). Specifically, the slit-like ejection port formed in the lower end part of the coating nozzle is moved close to the substrate, and a predetermined gap is formed and maintained between the ejection port and the substrate. Then, the coating liquid ejected from the ejection port is caused to be in contact with the substrate, and in that state, the substrate and the coating nozzle are relatively moved in a horizontal direction, for example, in a radial direction of the substrate. Consequently, the coating liquid is drawn out of the ejection port by the capillary phenomenon and the coating liquid is coated on the substrate.